This invention relates generally to an electrical connector incorporating passive circuit elements and methods of manufacturing such an electrical connector.
Modern electronic circuitry is often built on printed circuit boards. The printed circuit boards are then interconnected to create an electronic system, such as a server or a router for a communications network. Electrical connectors are generally used to make these interconnections between the printed circuit boards. Typically, connectors are made of two pieces, with one piece on one printed circuit board and the other piece on another printed circuit board. The two pieces of the connector assembly mate to provide signal paths between the printed circuit boards.
A desirable electrical connector should generally have a combination of several properties. For example, it should provide signal paths with appropriate electrical properties such that the signals are not unduly distorted as they move between the printed circuit boards. In addition, the connector should ensure that the two pieces mate easily and reliably. Furthermore, the connector should be rugged so that it is not easily damaged by handling of the printed circuit boards. For many applications, it is also important that the connector have high density, meaning that the connector can carry a large number of electrical signals per unit length.
Examples of electrical connectors possessing these desirable properties include VHDM®, VHDM®-HSD and GbX® connectors manufactured and sold by the assignee of the present invention, Amphenol Corporation.
One of the disadvantages of present electronic systems is the need, often times, to populate the surfaces of the interconnected printed circuit boards with passive circuit elements. These passive circuit elements, such as capacitors, inductors and resistors, are necessary, for example: (i) to block or at least reduce the flow of direct current (“DC”) caused by potential differences between various electronic components on the interconnected printed circuit boards; (ii) to provide desired filtering characteristics; and/or (iii) to reduce data transmission losses. However, these passive circuit elements take up precious space on the board surface (thus reducing the space available for signal paths). In addition, where these passive circuit elements on the board surface are connected to conductive vias, there could be undesirable signal reflections at certain frequencies due to impedance discontinuity and resonant stub effects.
Examples of thick film devices are shown in U.S. Pat. No. 3,582,729 to Girard, U.S. Pat. No. 2,774,747 to Wolfson, and U.S. Pat. No. 2,397,744 to Kertesz. Polymer thick films are discussed in Polymer Thick Film by Ken Gilleo, ©1996, and Creative Materials, Inc. of Tyngsboro, Mass. (www.creativematerials.com) offers a High Dielectric Constant Ink as well as a Pad-Printable, High Dielectric Strength Ink/Coating. These documents are incorporated herein by reference.
What is desired, therefore, is an electrical connector and methods of manufacturing such an electrical connector that generally possesses the desirable properties of the existing connectors described above, but also provides passive circuit elements in the connector to deliver the desired qualities provided by the passive circuit elements described above. And it is further desired that such an electrical connector provide the passive circuit elements cost effectively.